Anticipated Impacts on Veteran's Healthcare: Individuals with serious mental illness (SMI) have greater physical illness morbidity and mortality than the general population, but typically do not enroll in nor complete health promotion interventions. This pilot study will provide preliminary evaluation of a low- demand physical activity intervention that may be acceptable to Veterans with SMI and lead to improved health in this medically vulnerable population. Project Background: The relatively high rates of morbidity and mortality found among individuals with SMI have led to prioritization by Mental Health QUERI, and other groups, of prevention and health promotion in addition to improved coordination of physical health care for this population. Although promising health promotion interventions have been developed, they are intensive and none seem to successfully address the challenge of improving reach and enrollment while minimizing attrition. We propose to conduct a pilot evaluation of a novel low-demand intervention that may be an acceptable introduction to health promotion, the Get Moving and Get Well! (GMGW) program. Participants in the current version of GMGW have described benefits beyond those expected. We believe a 12-week GMGW program may be an effective and relatively low- demand intervention to promote self-efficacy and physical health in Veterans with SMI through increasing Veteran behavioral activation. Project Objectives: The objectives of the proposed study are to: (a) determine the effects of participation in the 12-week GMGW program on a measure of behavioral activation; (b) determine the effects of GMGW on measures of self-efficacy, physical activity, general physical and mental health, and mood; and (c) determine the effects of participation in the class on measures of intent to engage and actual engagement in more intensive physical health programs. Project Methods: In order to inform a future full scale study, we will complete the development of a 12-week manualized GMGW class, assess its acceptability, feasibility and time burden, and evaluate effects of the intervention on key outcome measures. To achieve the aims of the study, we will randomly assign 30 participants to either GMGW or an attention control condition. Participants will complete baseline measures investigating behavioral activation, self-efficacy, physical activity, physical and emotional health, mood, and intent to engage in health promotion activities before beginning the class. These measures will be repeated at the end of the 12-week class, along with questions investigating the acceptability of the interventions. A chart review will investigat actual engagement in health promotion interventions. We will be looking for the emergence of trends for differences in expected directions and response patterns within and between groups that will inform us about effect sizes for the measures and permit a power analysis for the full scale trial. We plan to use repeated measures analysis of variance, controlling for any variables that differ significantly between the intervention and control groups, to test the hypothesis that GMGW participants will have greater improvements on the measures at the end of the 12-week intervention than the control participants. Finally, we will also compare the number of participants who have evidence of participation in new health promotion activities in their medical record using a chi-square test of equal proportions.